When The Digital Output Values Cannot Be Read - Mitsubishi MELSEC Q Series User Manual

8 TROUBLESHOOTING

8.2.4 When the digital output values cannot be read

Is 24VDC external supply power being supplied?
(Q62AD-DGH only)
Is there any fault with the analog signal lines such as
disconnection (for the Q62AD-DGH, disconnection of the
signal line with the 2-wire transmitter) or wire break?
Is the CPU module in the STOP status?
Are the offset/gain settings correct?
Is the input range setting correct?
Is the A/D conversion enable/disable setting for the
channel to be used set to A/D conversion disabled?
Is a large value set as the A/D conversion starting time
setting? (Q62AD-DGH only)
Has the operating condition setting request (Y9) been
executed?
Are the (V+) and (I+) terminals connected in the case of
current input? (Q64AD-GH only)
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Check item
POINT
The module may be faulty if the digital output values cannot be read after proper
corrective actions have been taken according to the above check items. Consult
the nearest representative or branch.
Corrective action
Check that the external supply power terminals (terminal
Nos. 16, 17) are supplied with a 24VDC voltage.
Check for faulty condition of the lines visually and perform
a continuity check of the signal lines.
Set the CPU module to the RUN status.
Verify that the offset/gain settings are correct
(see Sections 4.6 and 5.6.2).
If the user range is being used, switch to a different default
input range and check if A/D conversion is correctly
performed. If it is correctly performed, redo the offset/gain
settings.
Check the buffer memory address 20 (Un\G20) in the
monitor of GX Developer.
If the input range setting is incorrect, redo the GX
Developer intelligent function module switch setting
(see Section 4.5).
Check the ON/OFF status with buffer memory 0 (Un\G0) in
GX Developer system monitor and review the initial setting
of the sequence program or utility package
(see Section 3.4).
Check the buffer memory addresses 5, 6 (Un\G5, Un\G6)
in the monitor of GX Developer.
From GX Developer, turn the operating condition setting
request (Y9) from ON to OFF to check that the digital
output values are stored into the buffer memory addresses
11 to 14 (Un\G11 to Un\G14), 54 to 61 (Un\G54 to
Un\G61).
If so, review the initial setting of the Sequence program or
utility package (see Section 3.3).
For current input, connect the (V+) and (I+) terminals,
referring Section 4.4.2.
MELSEC-Q
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